It has been well established that T-cells play an important role in regulating immune response (F. Powrie and R. L. Coffman, Immunol. Today, 14, p. 270 (1993)). Indeed, activation of T-cells is often the initiating event in many inflammatory and autoimmune diseases. IL-2 is an autocrine growth factor which plays an essential role in the regulation of T-cell activation and proliferation. Clinical studies have shown that interference with IL-2 activity effectively suppresses immune response in vivo (T. A. Waldmann, Immunol. Today, 14, 270 (1993)). Accordingly, agents which inhibit IL-2 production are therapeutically useful for selectively suppressing immune response in a patient in need of such immunosuppression.
Previously, others have attempted to interfere with the activity of IL-2 by using cytokine antagonists, monoclonal antibodies, toxins and other biologics which seek to prevent IL-2 from binding to its receptor (G. Mazur and I. Frydecka, Acta Haematol. Pol., 24(4), p. 307 (1993)). More recently, others have attempted to inhibit IL-2 production at the T cell level, for example by blocking the expression of IL-2 mRNA with glucocorticoids or cyclosporin A. However, to date, the reported compounds suffer from several disadvantages such as low potency, poor in vivo activity, toxicity and poor oral bioavailability. Accordingly, a need exists for compounds that can effectively inhibit IL-2 production for preventing and treating immune disorders.
A number of 3,5-disubstituted-1-(4-substituted)phenypyrazoles are available commercially or are known in the literature. These include N-{4-[3,5-bis(trifluoromethyl)pyrazol-1-yl]phenyl}-4-chlorobenzamide, N-{4-[3,5-bis(trifluoromethyl)pyrazol-1-yl]phenyl}-4-trifluoromethyoxybenzamid,e, N-{4-[3,5-bis(trifluoromethyl)pyrazol-1-yl]phenyl}-3,5-dimethylisoxazole-4-carboxamide, N-{4-[3,5-bis(trifluoromethyl)pyrazol-1-yl]phenyl}-4-methyl-1,2,3-thiadiazole-5-carboxamide, N-{4-[3,5-bis(trifluoromethyl)pyrazol-1-yl]phenyl}-Nxe2x80x2-(3,5-dichlorophenyl)urea, N-{4-[3,5-bis(trifluoromethyl)pyrazol-1-yl]phenyl}-Nxe2x80x2-(3,5-difluorophenyl)urea, and N-{4-[3,5-bis(trifluoromethyl)pyrazol-1-yl]phenyl}-Nxe2x80x2-n-propylurea which are available commercially as chemical intermediates from Maybridge Chemical Company Ltd., Trevillett, Tintagel, Cornwall PL34 OHW, UK.
N-[4-(3,5-dimethylpyrazol-1-yl)phenyl]acetamide (Bouchet and Coquelet, Bull. Soc. Chim.
Fr. 1976, 195), N-[4-(3-methyl-5-chloropyrazol-1-yl)phenyl]acetamide (Michaelis and Behn, Chem. Ber. 1900, 33, 2602), N-[4-(3-methyl-5-(methylthio)pyrazol-1-yl)phenyl]acetamide (Michaelis, Justus Liebigs Ann. Chem., 1911, 378, 346), N-[4-(3-methyl-5-phenylpyrazol-1-yl)phenyl]benzamide (Barry et al., J. Chem. Soc. 1956, 4974), N-[4-(3-methyl-5-ethoxypyrazol-1-yl)phenyl]acetamide (Hoechster Farbw., DE 92990), N-[4-(3,5-dimethylpyrazol-1-yl)phenyl]-4-methoxybenzylamine, N-[4-(3,5-dimethylpyrazol-1-yl)phenyl]-4-nitrobenzylamine (Fernandes et al. J. Indian Chem. Soc. 1977, 54, 923), 4-(3,5-dimethylpyrazol-1-yl)-N-methylbenzamide (Wright et al., J. Med. Chem. 1964, 7, 102), 4-methoxy- and 4-nitro-alpha-{[4-(3,5-dimethylpyrazol-1-yl)phenyl]amino}benzeneacetonitrile and N-[4-(3,5-dimethylpyrazol-1-yl)phenyl]-4-methoxy-(and 4-nitro)-benzenemethaneamine (Fernandes et al., J. Indian Chem. Soc. 1977, 54, 923) are described in the chemical or patent literature. In no case is antiinflammatory activity or ability to inhibit IL-2 production associated with or described for any of these compounds.
1-(4-Methylaminophenyl)-5-(4-methylsulfonylphenyl)-3-trifluoromethylpyrazole, 1-(4-methylaminophenyl)-5-(4-methylsulfonylphenyl)-3-difluoromethylpyrazole (K. Tsuji et al., Chem. Pharm. Bull., 1997, 45, 1475) and 3-cyano-1-(4-methylaminophenyl)-5-(4-methylsulfonylphenyl)pyrazole and 3-cyano-1-(4-ethylaminophenyl)-5-(4-methylsulfonylphenyl)pyrazole (K. Tsuji et al., Chem Pharm. Bull. 1997, 45, 987) are among several compounds described as having antiinflammatory activity due to their ability to inhibit an isoform of cyclooxygenase referred to as COX-2. In neither case is the inhibition of IL-2 production mentioned.
Among a series of substituted pyrazoles having antiinflammatory activity described by M. Matsuo (EP 418845 A1) are 1-[4-(C1-C6 alkylamino)phenyl]- and [4-(C1-C6 acylamino)phenyl]pyrazoles substituted on the pyrazole on either the 3-,4-, or 5-position with CF3, halogen, dimethylaminomethyl, CN, C1-6 alkylthio, or esterified carboxy and on another of the 3-, 4-, or 5-positions with a substituted aryl or heteroaryl ring. No mention is made of inhibition of IL-2 production.
The compounds of this invention are 1-(4-aminophenyl)pyrazoles optionally substituted on the 3- and 5-positions of the pyrazole ring and on the amino group on the 4-position of the phenyl ring having antiinflammatory activity by virtue of their ability to inhibit IL-2 production in T-lymphocytes.
In its broadest generic aspect, the invention comprises 1(4-amninophenyl)pyrazoles of Formula I 
wherein:
R1 and R3 are the same or different and each is CF3, halogen, CN, C1-8 alkyl or branched alkyl or C1-8 alkenyl or branched alkenyl or C3-8 cycloalkyl optionally substituted with OH, CN or methoxy; C1-8 alkoxy, C1-4 alkyloxyalkyl, C1-8 alkylthio, C1-4 alkylthioalkyl, C1-8 dialkylamino, C1-4 dialkylaminoalkyl, CO2R5 where R5 is C1-4 alkyl or C1-4 alkenyl optionally substituted with carbocyclyl or heterocyclyl; aryl or heterocyclyl connected to the pyrazole in any position that makes a stable bond, optionally substituted with halogen, C1-4 alkyl, C1-4 alkenyl, CN, Me2N, CO2Me, OMe, aryl, heterocyclyl or R5.
R2 is H, halogen, or methyl.
L is xe2x80x94NHC(O)xe2x80x94, xe2x80x94NHC(O)Oxe2x80x94, xe2x80x94NHC(O)C(O)xe2x80x94, xe2x80x94NHC(S)xe2x80x94, xe2x80x94NHxe2x80x94, xe2x80x94NHC(O)NH, NHC(S)NH, NHCH2, xe2x80x94NHCH(R6)xe2x80x94, where R6 is H, CN, C1-6 alkyl, C1-6 alkyloxyoalkyl C1-6 alkythioalkyl, C1-6 alkylsulfinylalkyl, C1-6 alkysulfonylalkyl, C3-6 cycloalkyl, or heterocyclyl or aryl optionally substituted with a halogen, C1-4 alkyl, CN, Me2N, CO2Me or OMe, or xe2x80x94NHC(R6)xe2x80x94 lower alkyl.
R4 is C1-8 alkyl, C1-8 alkyloxy, C1-8 alkylthio, C1-8 alkylamino, C1-4 alkoxyalkyl, C1-4 alkylthioalkyl, C1-4 alkylaminoalkyl, C1-4 dialkylalkylaminoalkyl, carbocyclyl or heterocyclyl, optionally substituted with one or more halogen, xe2x80x94CN, xe2x80x94NO2, SO2NH2, or R7 where R7 is phenyl, heterocyclyl, C3-6 cycloalkyl, C1-6 alkyl, C2-6 alkenyl, C1-6 alkyloxyalkyl, C1-6 alkylthioalkyl, C1-6 alkylsulfinylalkyl, C1-6 alkylsulfonylalkyl or C2-6 alkynyl, optionally substituted with halogen, OH, alkyloxy, CN, COO-lower alkyl, xe2x80x94CONH-lower alkyl, xe2x80x94CON(lower alkyl)2, dialkylamino, phenyl or heterocylcyl; CO2R7, xe2x80x94N(R7)2, xe2x80x94NH(R7), xe2x80x94C(O)R7, xe2x80x94OR7, S(O)nR7 where n is 0, 1 or 2, xe2x80x94SO2NHR7, xe2x80x94SO2N(R7)2.
In order that the invention herein described may be more fully understood, the following detailed description is set forth. As used herein, the following abbreviations are used:
BOC or t-BOC is tertiary butoxycarbonyl
DMAP is 4-dimethylamino pyridine
Bu is butyl
DIBAL is diisobutylaluminum hydride
DMF is dimethylformamide
Et is ethyl
Me is methyl
Oxz is oxazole
Ph is phenyl
Pr is propyl
Py is pyridine
PyBOP is Benzotriazole-1-yl-oxy-tris-pyrrolidino-phosphonium hexafluorophosphate
Th is thiophene
THF is tetrahydrofuran
Thz is thiazole
Rt is room temperature
EDC is 1-(3-dimethylaminopropyl)-3-ethylcarbodimide hydrochloride.
Also, as used herein, each of the following terms, used alone or in conjunction with other terms, are defined as follows (except where noted to the contrary):
The term xe2x80x9calkylxe2x80x9d refers to a saturated aliphatic radical containing from one to ten carbon atoms. xe2x80x9cAlkylxe2x80x9d refers to both branched and unbranched alkyl groups. Preferred alkyl groups are straight chain alkyl groups containing from one to eight carbon atoms and branched alkyl groups containing from three to eight carbon atoms. More preferred alkyl groups are straight chain alkyl groups containing from one to six carbon atoms and branched alkyl groups containing from three to six carbon atoms. xe2x80x9cAlkylxe2x80x9d, as used herein, includes unsubstituted alkyl radicals, those radicals that are partially or fully halogenated and those radicals substituted with one to four, preferably one or two, substituents selected from amino, cyano, nitro, methoxy, ethoxy and hydroxy. The term xe2x80x9ccycloalkylxe2x80x9d refers to the cyclic analog of an alkyl group, as defined above. Preferred cycloalkyl groups are saturated cycloalkyl groups containing from three to eight carbon atoms, and more preferably three to six carbon atoms. xe2x80x9cAlkylxe2x80x9d and xe2x80x9ccycloalkylxe2x80x9d, as used herein, include unsubstituted alkyl and cycloalkyl radicals, those radicals that are partially or fully halogenated and those radicals substituted with one to four, preferably one or two, substituents selected from halo, amino, cyano, nitro, methoxy, ethoxy and hydroxy. It should be understood that any combination term using an xe2x80x9calkxe2x80x9d or xe2x80x9calkylxe2x80x9d prefix refers to analogs according to the above definition of xe2x80x9calkylxe2x80x9d. For example, terms such as xe2x80x9calkoxyxe2x80x9d, xe2x80x9callkythioxe2x80x9d refer to alkyl groups linked to a second group via an oxygen or sulfur atom.
The terms xe2x80x9calkenylxe2x80x9d and xe2x80x9calkynylxe2x80x9d refer to a mono- or polyunsaturated aliphatic hydrocarbon radical containing from two to twelve carbon atoms, containing at least one double or triple bond, respectively. xe2x80x9cAlkenylxe2x80x9d and xe2x80x9calkynylxe2x80x9d refer to both ranched and unbranched alkenyl and alkynyl groups. Preferred alkenyl and alkynyl groups are straight chain alkenyl or alkynyl groups containing from two to eight carbon atoms and branched alkenyl or alkynyl groups containing from five to ten carbon atoms. More preferred alkenyl and alkynyl groups are straight chain alkenyl or alkynyl groups containing from two to six carbon atoms and branched alkenyl or alkynyl groups containing from five to eight carbon atoms. The term xe2x80x9ccycloalkenylxe2x80x9d refers to the cyclic analog of an alkenyl group, as defined above. Preferred cycloalkenyls include cycloalkenyl rings containing from three to eight carbon atoms, and more preferably, from three to six carbon atoms. xe2x80x9cAlkenylxe2x80x9d, xe2x80x9calkynylxe2x80x9d and xe2x80x9ccycloalkenylxe2x80x9d, as used herein, include unsubstituted alkenyl or alkynyl radicals, those radicals that are partially or fully halogenated and those radicals substituted with one to four, preferably one or two, substituents selected from halo, amino, cyano, nitro, methoxy, ethoxy and hydroxy.
The term xe2x80x9carylxe2x80x9d refers to phenyl and naphthyl, phenyl and naphthyl that are partially or fully halogenated and phenyl and naphthyl substituted with halo, alkyl, hydroxyl, nitro, xe2x80x94COOH, xe2x80x94CO(lower alkoxy), xe2x80x94CO(lower alkyl), amino, alkylamino, dialkylamino, alkoxy, xe2x80x94NCOH, xe2x80x94NCO(lower alkyl), xe2x80x94NSO2xe2x80x94Ph(halo)0-3, Ph, xe2x80x94Oxe2x80x94Ph; naphthyl, xe2x80x94O-naphthyl, pyrrolyl, pyrrolyl substituted with lower alkyl, pyridyl, pyridinyl, pyrazinyl, pyrimidinyl and pyridazinyl.
The term xe2x80x9ccarboxy alkylxe2x80x9d refers to an alkyl radical containing a xe2x80x94COOH substituent.
The term xe2x80x9chaloxe2x80x9d refers to a halogen radical selected from fluoro, chloro, bromo or iodo. Preferred halo groups are fluoro, chloro and bromo.
The term xe2x80x9ccarbocyclylxe2x80x9d refers to a stable 3-8 membered (but preferably, 5 or 6 membered) monocyclic or 7-11 membered bicyclic radical which may be either saturated or unsaturated, aromatic or non-aromatic. Preferred carbocycles include, for example, phenyl, naphthyl, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclopentenyl, cyclohexenyl, cycloheptenyl, indanyl, indenyl, dihydronaphthyl and tetrahydronaphthyl. xe2x80x9cCarbocyclylxe2x80x9d refers to unsubstituted carbocyclic radicals, those radicals that are partially or fiully halogenated and those radicals substituted with alkyl; hydroxyl; nitro; xe2x80x94COOH; xe2x80x94CO(lower alkoxy); xe2x80x94CO(lower alkyl); amino; alkylamino; dialkylamino; alkoxy, xe2x80x94NCHO; xe2x80x94NCO(lower alkyl); xe2x80x94NSO2-Ph(halo)0-3, Ph; xe2x80x94Oxe2x80x94Ph; naphthyl; xe2x80x94O-naphthyl; pyrrolyl; pyrrolyl substituted with lower alkyl; pyridyl; pyridinyl; pyrazinyl; pyrimidinyl and pydazinyl.
The term xe2x80x9cheterocyclexe2x80x9d refers to a stable 5-8 membered (but preferably, 5 or 6 membered) monocyclic or 8-11 membered bicyclic heterocycle radical which may be either saturated or unsaturated, aromatic or non-aromatic, and which may be optionally benzo- or pyridofused if monocyclic. Each heterocycle consists of carbon atoms and from 1 to 4 heteroatoms selected from the group consisting of nitrogen, oxygen and sulfur. As used herein, xe2x80x9cnitrogenxe2x80x9d and xe2x80x9csulfurxe2x80x9d include any oxidized form of nitrogen and sulfur and the quaternized form of any basic nitrogen. The heterocycle may be attached by any atom of the cycle, which results in the creation of a stable structure. Preferred heterocycles include, for example, benzimidazolyl, furyl; imidazolyl, imidazolinyl, imidazolidinyl, quinolinyl, isoquinolinyl, indolyl, oxazolyl, pyridyl, pyrrolyl, pyrrolinyl, pyrazolyl, pyrazinyl, pyrimidinyl, pyridazinyl, quinoxolyl, piperidinyl, morpholinyl, thiomorpholinyl, furyl, thienyl, triazolyl, thiazolyl, xcex2-carbolinyl, tetrazolyl, thiazolidinyl, benzofuranoyl, thiamorpholinyl sulfone, benzoxazolyl, oxopiperidinyl, oxopyrroldinyl, oxoazepinyl, azepinyl, isoxazolyl, tetrahydropyranyl, tetrahydrofuranyl, thiadiazoyl, benzodioxolyl, tetrahydrothiophenyl and sulfolanyl. Most preferred heterocycles of this invention include imidazolyl, pyridyl, pyrrolyl, pyrazolyl, piperidinyl, morpholinyl, furyl, thienyl, thiazolyl and the benzo- and pyrido-flised derivatives thereof. xe2x80x9cHeterocyclylxe2x80x9d refers to unsubstituted heterocycle radicals, those radicals that are partially or fully halogenated and those radicals substituted with alkyl; hydroxyl; nitro; xe2x80x94COOH; xe2x80x94CO(lower alkoxy); xe2x80x94CO(lower alkyl); amino; alkylamino; dialkylamino; alkoxy; xe2x80x94NCHO; xe2x80x94NCO(lower alkyl); xe2x80x94NSO2xe2x80x94Ph(halo)0-3, Ph; xe2x80x94Oxe2x80x94Ph; naphthyl; xe2x80x94O-naphthyl; pyrrolyl; pyrrolyl substituted with lower alkyl; pyridyl; pyridinyl; pyrazinyl; pyrimidinyl and pyridazinyl.
The term xe2x80x9clowerxe2x80x9d used in conjunction with other terms (e.g., xe2x80x9calkylxe2x80x9d, xe2x80x9calkoxyxe2x80x9d and the like) refers to a radical containing from one to six, preferably from one to five and more preferably, from one to four carbon atoms. For example, a xe2x80x9clower alkylxe2x80x9d group is a branched or unbranched alkyl radical containing from one to six carbon atoms.
The term xe2x80x9cpatientxe2x80x9d refers to a warm-blooded animal, and preferably human.
The term xe2x80x9cpreventionxe2x80x9d or xe2x80x9cprophylaxisxe2x80x9d refers to a measurable reduction in the likelihood of a patient acquiring a disease or disorder.
The term xe2x80x9ctreatmentxe2x80x9d refers to either the alleviation of the physical symptoms of a disease or an improvement in the physiological markers used to measure progression of a disease state.
The term xe2x80x9cpharmaceutically acceptable carrierxe2x80x9d or xe2x80x9cpharmaceutically acceptable adjuvantxe2x80x9d refers to a non-toxic carrier or adjuvant that may be administered to a patient together with a compound of this invention and which does not destroy the pharmacological activity of that compound.
The term xe2x80x9cpharmaceutically effective amountxe2x80x9d refers to an amount effective in suppressing the immunity of a patient in need of such treatment. Suppressed immunity can be readily measured by observing the degree of inhibition of IL-2 production in human T-cells (PBLS) by known techniques.
The term xe2x80x9cprophylactically effective amountxe2x80x9d refers to an amount effective in preventing or reducing the likelihood of initial onset or progression of an immune disorder in a patient susceptible to such disorder.
It should be understood that any compounds of this invention containing one or more asymmetric carbon atoms may occur as racemates and racemic mixtures, single enantiomers, diastereomeric mixtures and individual diastereomers. All such isomeric forms of these compounds are expressly included in the present invention. Each stereogenic center may be in the R or S configuration, or a combination of configurations.
The compounds of this invention are defined to include pharmaceutically acceptable derivatives thereof. A xe2x80x9cpharmaceutically acceptable derivativexe2x80x9d refers to any pharmaceutically acceptable salt, ester, or salt of an ester of a compound of this invention, or any other compound which, upon administration to a patient, is capable of providing (directly or indirectly) a compound of this invention, a pharmacologically active metabolite or pharmacologically active residue thereof.
Combinations of substituents and variables encompassed by this invention are only those that result in the formation of stable compounds. The term xe2x80x9cstablexe2x80x9d as used herein, refers to compounds which possess stability sufficient to permit manufacture and administration to a patient by conventional methods known in the art. Typically, such compounds are stable at a temperature of 40xc2x0 C. or less, in the absence of moisture or other chemically reactive conditions, for at least a week.
The compounds of this invention may be used in the form of salts derived from inorganic or organic acids. Included among such acid salts, for example, are the following: acetate, adipate, alginate, aspartate, benzoate, benzenesulfonate, bisulfate, butyrate, citrate, camphorate, camphorsulfonate, cyclopentanepropionate, digluconate, dodecylsulfate, ethanesulfonate, fumarate, glucoheptanoate, glycerophosphate, hemisulfate, heptanoate, hexanoate, hydrochloride, hydrobromide, hydroiodide, 2-hydroxyethanesulfonate, lactate, maleate, methanesulfonate, 2-naphthalenesulfonate, nicotinate, oxalate, pectinate, persulfate, 3-phenylpropionate, picrate, pivalate, propionate, succinate, tartrate, tosylate and undecanoate.
This invention relates to substituted 1-(4-aminophenyl)pyrazoles and analogs thereof that inhibit interleukin-2 (IL-2) production. In one embodiment, this invention relates to a novel class of substituted 1-(4-aminophenyl)pyrazoles and pharmaceutical compositions comprising these compounds. This invention also relates to methods for producing such novel substituted 1(4-aminophenyl)pyrazoles. Because of their selective immunomodulating properties, the compounds and pharmaceutical compositions of this invention are particularly well suited for preventing and treating immune disorders, including autoimmune disease, inflammatory disease, organ transplant rejection and other disorders associated with IL-2 mediated immune response.
The substituted 1(4-aminophenyl)pyrazoles of this invention are represented by Formula I 
wherein:
R1 and R3 are the same or different and each is CF3, halogen, CN, C1-8 alkyl or branched alkyl or C1-8 alkenyl or branched alkenyl or C3-8 cycloalkyl optionally substituted with OH, CN or methoxy; C1-8 alkoxy, C1-4 alkyloxyalkyl, C1-8 alkylthio, C1-4 alkylthioalkyl, C1-8 dialkylamino, C1-4 dialkylaminoalkyl, CO2R5 where R5 is C1-4 alkyl or C1-4 alkenyl optionally substituted with carbocyclyl or heterocyclyl; aryl or heterocyclyl connected to the pyrazole in any position that makes a stable bond, optionally substituted with halogen, C1-4 alkyl, C1-4 alkenyl, CN, Me2N, CO2Me, OMe, aryl, heterocyclyl or R5.
R2 is H, halogen or methyl.
L is xe2x80x94NHC(O)xe2x80x94, xe2x80x94NHC(O)Oxe2x80x94, xe2x80x94NHC(O)C(O)xe2x80x94, xe2x80x94NHC(S)xe2x80x94, xe2x80x94NHxe2x80x94, xe2x80x94NHC(O)NH, NHC(S)NH, NHCH2, xe2x80x94NHCH(R6)xe2x80x94, where R6 is H, CN, C1-6 alkyl, C1-6 alkyloxyoalkyl C1-6 alkythioalkyl, C1-6 alkylsulfinylalkyl, C1-6 alkysulfonylalkyl, C3-6 cycloalkyl, or heterocyclyl or aryl optionally substituted with a halogen, C1-4 alkyl, CN, Me2N, CO2Me or OMe, or xe2x80x94NHC(R6)xe2x80x94 lower alkyl.
R4 is C1-8 alkyl, C1-8 alkyloxy, C1-8 alkylthio, C1-8 alkylamino, C1-4 alkoxyalkyl, C1-4 alkylthioalkyl, C1-4 alkylaminoalkyl, C1-4 dialkylalkylaminoalkyl, carbocyclyl or heterocyclyl, optionally substituted with one or more halogen, xe2x80x94CN, xe2x80x94NO2, SO2NH2, or R7 where R7 is phenyl, heterocyclyl, C3-6 cycloalkyl, C1-6 alkyl, C2-6 alkenyl, C1-6 alkyloxyalkyl, C1-6 alkylthioalkyl, C1-6 alkylsulfinylalkyl, C1-6 alkylsulfonylalkyl or C2-6 alkynyl, optionally substituted with halogen, OH, alkyloxy, CN, COO-lower alkyl, xe2x80x94CONH-lower alkyl, xe2x80x94CON(lower alkyl)2, dialkylamino, phenyl or heterocylcyl; CO2R7, xe2x80x94N(R7)2, xe2x80x94NH(R7), xe2x80x94C(O)R7, xe2x80x94OR7, S(O)nR7 where n is 0, 1 or 2, xe2x80x94SO2NHR7, xe2x80x94SO2N(R7)2.
Preferably, the novel substituted 1-(4-aminophenyl)pyrazoles of Formula I are those wherein:
R1 is straight-chained, branched or cyclo-C3-8 alkyl, alkenyl, or alkynyl; C1-3 alkyloxyalkyl, C1-5 alkyloxy, C1-3alkylthioalkyl, C1-5 alkylthio, CF3; heterocyclyl or aryl optionally substituted with halogen, C1-4 alkyl, CN, alkoxy or Me2N;
R2 is H; and
R3 is halogen, Me, Et, CF3, CN, cyclopropyl, vinyl, SMe, OMe, heterocyclyl or aryl optionally substituted with halogen, C1-4 alkyl, CN, alkoxy or Me2N;
L is xe2x80x94NHC(O)xe2x80x94, xe2x80x94NHxe2x80x94, xe2x80x94NHC(O)NH, xe2x80x94C(O)NH, or xe2x80x94NHCH(R6)xe2x80x94, where R6 is H, C1-4 alkyl, or CN and
R4 is C1-6 alkyl, C1-4 alkyloxyalkyl, C1-4 alkylthioalkyl, cyclohexyl, cyclopentyl, indanyl, indolyl, phenyl, thienyl, naphthyl, isoxazolyl or pyridyl, optionally substituted with one or more halogen, xe2x80x94CN, xe2x80x94NO2, SO2NH2, or R7 where R7 C1-6 alkyl, C2-6 alkenyl, C1-6 alkyloxyalkyl, C1-6 alkylthioalkyl, or C2-6 alkynyl, optionally substituted with OH, CN, xe2x80x94COO-lower alkyl, xe2x80x94CONH-lower alkyl, xe2x80x94CON(lower alkyl)2, dialkylamino, or heterocylcyl; CO2R7, xe2x80x94N(R7)2, xe2x80x94NH(R7), xe2x80x94C(O)R7, xe2x80x94OR7, S(O)nR7 where n is 0, 1 or 2, xe2x80x94SO2NHR7, xe2x80x94SO2N(R7)2.
More preferred are novel substituted 1-(4-aminophenyl)pyrazoles of Formula I wherein:
R1 is Et, i-Pr, t-Bu, cyclopentyl, CF3, -OEt, MeOCH2xe2x80x94, 2- or 3-tetrahydrofuranyl, 2-, 3-, or 4-pyridyl or 2-pyrazinyl;
R2 is H;
R3 is Halogen, CN, CF3, Me, 5Me or Et;
L is xe2x80x94NHC(O)xe2x80x94, xe2x80x94NHxe2x80x94 or xe2x80x94NHCH2xe2x80x94; and
R4 is alkyl, cyclohexyl, cyclopentyl, indanyl, indolyl, phenyl, thienyl, naphthyl, or pyridyl, optionally substituted with one or more halogen, xe2x80x94CN, or R7 where R7 C1-6 alkyl, C2-6 alkenyl, C1-6 alkyloxyalkyl, C1-6 alkylthioalkyl, optionally substituted with OH, CN, or heterocylcyl; xe2x80x94CO2R7, xe2x80x94N(R7)2, xe2x80x94NH(R7), xe2x80x94C(O)R7, or xe2x80x94OR7.
Compounds of Formula I in which L is xe2x80x94NHC(O)xe2x80x94 may be prepared by one of the methods outlined below. For example, a (4-aminophenyl)-3,5-disubstituted pyrazole 1 may be reacted with a carboxylic acid 2 under suitable coupling conditions known to one skilled in the art, for example EDC and a base catalyst such as N,N-dimethylaminopyridine in a suitable solvent such as methylene chloride acetonitrile or DMF (Method A). Alternatively, 1 could be coupled with an acid halide 3 in the presence of a suitable base such as triethylamine in a suitable solvent such as methylene chloride (Method B). In another alternative method, these compounds could be prepared by reacting a 4-(acetamido)phenylhydrazine 4 with a 1,5-disubstituted-2,4-pentanedione 5 in a suitable solvent such as acetic acid (Method C). If R1 is different from R3, then two different products may form using Method C, which may be separated by techniques such as chromatography known to those skilled in the art. 
Compounds of Formula I in which L is xe2x80x94NHxe2x80x94 and R4 is a heteroaryl ring may be prepared, as illustrated below, by reaction of a (4-aminophenyl)-3,5-disubstituted pyrazole 1 with a heterocycle 6 containing a labile substituent such as a halogen, which may be displaced by nucleophilic substitution (Method D). The reaction may be carried out in a sealed tube or an open vessel, at ambient temperature or heated to 150xc2x0 C. in a suitable solvent such as dioxane or THF. A base such as sodium bis-trimethylsilyl amide may be added to the reaction. 
Compounds in which L is xe2x80x94NHC(O)NHxe2x80x94 may be prepared by reaction of isocyanate 7 with an amine 8 in a suitable solvent such as methylene chloride or toluene (Method E). An amine such as triethylamine may be added. Alternatively, 1 could be reacted with an amine carbonyl chloride such as N-morpholine carbonyl chloride 9 in a suitable solvent such as methylene chloride (Method F). 
Methods by which compounds in which L is xe2x80x94NHCH(R5)xe2x80x94 or xe2x80x94NHCH2 may be prepared as illustrated below. For example, these compounds may be prepared by reduction of the corresponding amide (L is xe2x80x94NHC(O)xe2x80x94) with a suitable reducing agent such as lithium aluminum hydride, in a suitable solvent such as THF or diethyl ether (Method G). Alternatively, amine 1 could react with an alkylating agent 10 (Method H) where X is a suitable leaving group such as a halogen. In another alternate procedure, amine 1 could react with an aldehyde 11, and the intermediate imine 12 reacted with a reducing agent such as sodium cyanoborohydride or sodium triacetoxyborohydride (Method I). Alternatively, 12 could be reacted with a nucleophile such as an alkyl or aryl lithium reagent (Method J).
Pyrazole intermediates used in the preparations of the compounds of the invention may be prepared by methods known in the chemical literature. Two general methods that may be used are illustrated below. For example, a disubstituted 1,3-dione 13 may be heated with 4-nitrophenylhydrazine in a suitable solvent such as ethanol to provide a 3,5-disubstituted 1-(4-nitrophenyl)pyrazole. If R1 and R3 are not equivalent, a mixture of two 
products may be obtained (Method K). Alternately, a 3,5-disubstituted pyrazole may be reacted with nitrobenzene substituted in the 4-position with a leaving group such as a halogen in the presence of a base (Method L). The nitrophenylpyrazoles produced by either method could then be reduced to aminophenyl pyrazoles by using a reducing agent such as SnCl2 or hydrogen or a hydrogen source such as ammonium formate in the presence of a catalyst such as palladium.
Certain R1 and R3 can greatly enhance the regioselectivity of the reaction to produce 14 by Method L. If R1 is aryl, and preferably an electron deficient aryl, such as pyridine, or a phenyl with an electron withdrawing group such as xe2x80x94CN or NO2, and R3 is alkyl, preferably ethyl or methyl, high regioselectivity to give 14 as the major product compared to regioisomer 14a can be obtained (Scheme I) by reacting the substituted pyrazole with a nitrobenzene substituted in the 4-position with a leaving group, preferably fluorine in a suitable solvent, preferably DMSO, with a suitable base, preferably t-BuOK at about 75xc2x0 C. for about one hour. 
One may obtain 14 where R1 is alkyl in a regioselective manner using Method L, by employing a substituted pyrazole where R1 contains a chelating group, preferably oxygen, and then converting R1 in the resulting product 14 to an alkyl group. For example, as illustrated in Scheme I, reacting a substituted pyrazole where R1 is an alkylcarbonyl, preferably xe2x80x94C(O)CH3, or an ether such as CH(R)ORxe2x80x2, where R is preferably hydrogen or methyl, and Rxe2x80x2 is a suitable protecting group, preferably tetrahydropyranyl (THP) with a nitrobenzene substituted in the 4-position with a leaving group, preferably fluorine, in a suitable solvent, such as THF or DMSO, preferably THF in the presence of a suitable base such as t-BuOK, n-BuLi, sodium hydride, or ethyl magnesium bromide, preferably t-BuOK, one obtains regioisomer 14 as the major product.
R1 may be converted to an alkyl group as illustrated in Scheme II 
As shown for 14 where R1 is an ether and Rxe2x80x2=THP, reaction with an acid, such as p-toluenesulfonic acid in a suitable solvent such as aqueous methanol provides alcohol 14b. Treatment with a suitable oxidizing agent such as pyridinium chlorochromate provides ketone 14c. Wittig reaction with a phosphorous ylide derived from methyltriphenylphosphonium bromide provides olefin 14d. Reaction under reducing conditions, such as hydrogenation in the presence of a palladium catalyst provides 15. Starting with 14 where R1 is an alkylcarbonyl, one would proceed beginning with 14c.
Other methods may also be used for synthesis of pyrazole intermediates. Some of these approaches are illustrated below. 5-Dimethylaminomethylpyrazole 16 may be prepared by a general method (Method M) described in the chemical literature (Tang and 
Hu, 1994, J. Chem. Soc. Chem. Commun., 631). The 1-(4-aminophenyl)pyrazole analog of 16 may then be prepared as described in Method L. Using nitrile 17 and 4-nitrophenylhydrazine, the 5-amino and 5-disubstituted aminopyrazoles 18 and 19 can be prepared (Method N). Reaction of hydrazone 20, with acrylonitrile and iodobenzene diacetate, followed by oxidation of pyrazoline 21 provides 5-cyanopyrazoles 22 (Method O). The nitrophenylpyrazoles described in Methods N and O can then be reduced to the aminophenylpyrazoles as described in Method L.
5-Cyanopyrazoles may also be obtained by method P below. 
Another procedure where one may regioselectively prepare substituted arylpyrazoles is illustrated by Method Q. 
Reaction of ketoester 23 with 4-nitrophenylhydrazine in a suitable solvent, preferably acetic acid at about reflux temperature provides 24. Treatment with a halogenating agent such as phosphorous tribromide or phosphorous oxychloride provides 25 where X=Br or Cl respectively. If desired, 25 (preferably X=Br) may be elaborated further, for example by transition metal catalyzed cross coupling reactions.
For example, as illustrated in Method R, 25a may be cross coupled with a terminal acetylene 26, where W may be, for example, hydrogen, or an alkyl group or any other group not adversely affecting the reaction, using conditions described by T. Sakamoto et al., (Synthesis, 1983, 312) to provide an alkyne at R3 (14a). Alternatively, reaction with vinylstannanes 27, W defined as above, under conditions described by J. W. Stille (Angew. Chem. Int. Ed. Engl., 1986, 25, 508), provides an alkene at R3 (Method S). Reaction with substituted or unsubstituted aryl- or heteroarylboronic acids under conditions described by N. Miyaura et al. (Chem. Rev. 1995, 95, 2457) provides 14c with aryl or heteroaryl groups at R3 (Method T). Alkynes 14a and alkenes 14b may be converted to the corresponding alkyl groups by reduction with a suitable reducing agent such as hydrogen in the presence of a suitable catalyst such as platinum or palladium to provide 1 (see Method L), with an alkyl group at R3. Alternatively, reaction with a reducing agent that leaves alkenes and alkynes intact, such as SnCl2 provides 1 with alkenes or alkynes at R3. 
Method U describes an alternate procedure for preparing compounds of Formula I where L is xe2x80x94NHxe2x80x94. Intermediate 1 may be heated at about 70xc2x0 C. with an aryl bromide in the presence of a palladium catalyst, preferably Pd2(dba)3, 2,2xe2x80x2-bis(diphenylphosphino)-1,1xe2x80x2-binapthyl (BINAP), and a base, preferably NaOt-Bu, in a solvent such as toluene, as described by S. Buchwald et al.(J. Amer. Chem. Soc., 1993, 119, 8451). Alternately, one could employ the same conditions with the bromophenylpyrazole 29 and an amine, R4NH2. 
As can be appreciated by chemists possessing ordinary skill in the art, the synthetic schemes described above are for illustrative purposes only and may be modified using conventional synthetic methodology to produce any of the analogs of Formula I. Depending on precisely how the synthetic schemes are modified, the specific reaction conditions might also require modification. Such modifications may involve the use of higher or lower temperature or pressure, conditions other than those reported herein, or the addition of further synthetic steps such as functional group transformations. However, since progress of the reactions is easily monitored by techniques such as high performance liquid chromatography, gas chromatography, mass spectroscopy, thin layer chromatography, nuclear magnetic resonance spectroscopy and the like, such modifications are well within the skill of the art. Likewise, it should be appreciated that initial products from these Methods could be further modified to make additional compounds of this invention. Intermediates used in the Methods described above may be commercially available or could be prepared from commercially available materials by methods described in the chemical literature and known to people skilled in the art.
The 1-phenylpyrazole analogs of Formula I inhibit production of IL-2. Without wishing to be bound by theory, the compounds of this invention inhibit IL-2 production by T cells. This inhibition of IL-2 production is therapeutically useful for selectively suppressing immune function. The result of such selectively suppressed immunity includes reduced cell proliferation of peripheral blood lymphocytes and cellular immune response. Thus, the inhibition of IL-2 production is an attractive means for preventing and treating a variety of immune disorders, including inflammatory diseases, autoimmune diseases, organ and bone marrow transplant rejection and other disorders associated with IL-2 mediated immune response. In particular, the compounds of Formula I may be used to prevent or treat acute or chronic inflammation, allergies, contact dermatitis, psoriasis, rheumatoid arthritis, multiple sclerosis, type 1 diabetes, inflammatory bowel disease, Guillain-Barre syndrome, Crohn""s disease, ulcerative colitis, graft versus host disease (and other forms of organ or bone marrow transplant rejection) and lupus erythematosus. Other disorders associated with IL-2 mediated immune response will be evident to those of ordinary skill in the art and can also be treated with the compounds and compositions of this invention.
The compounds of this invention may be administered in any conventional dosage form in any conventional manner. Such methods of treatment, including their dosage levels and other requirements, may be selected by those of ordinary skill in the art from available methods and techniques. For example, a compound of this invention may be combined with a pharmaceutically acceptable carrier or adjuvant for administration to a patient in need of such treatment in a pharmaceutically acceptable manner and in an amount effective to treat (including lessening the severity of symptoms) the immune disorder.
The compounds of this invention may be administered alone or in combination with conventional therapeutics, such as conventional immunosuppressants. Advantageously, such combination therapies utilize lower dosages of the conventional therapeutics, thus avoiding possible toxicity and adverse side effects incurred when those agents are used as monotherapies. The compounds of this invention may be physically combined with the conventional therapeutics into a single pharmaceutical composition. Advantageously, the compounds may then be administered together in a single dosage form. Alternatively, the compounds may be administered separately (either serially or in parallel). Separate dosing allows for greater flexibility in the dosing regime.
According to this invention, the compounds of Formula I and the pharmaceutical compositions containing those compounds may be administered to a patient in any conventional manner and in any pharmaceutically acceptable dosage from, including, but not limited to, intravenously, intramuscularly, subcutaneously, intrasynovially, by infusion, sublingually, transdermally, orally, topically or by inhalation. The preferred modes of administration are oral and intravenous.
Dosage forms of the compounds of this invention include pharmaceutically acceptable carriers and adjuvants known to those of ordinary skill in the art. These carriers and adjuvants include, for example, ion exchangers, alumina, aluminum stearate, lecithin, serum proteins, buffer substances, water, salts or electrolytes and cellulose-based substances. Preferred dosage forms include, tablet, capsule, caplet, liquid, solution, suspension, emulsion, lozenges, syrup, reconstitutable powder, granule, suppository and transdermal patch. Methods for preparing such dosage forms are known (see, for example, H. C. Ansel and N. G. Popovish, Pharmaceutical Dosage Forms and Drug Delivery Systems, 5th ed., Lea and Febiger (1990)). Dosage levels and requirements are well-recognized in the art and may be selected by those of ordinary skill in the art from available methods and techniques suitable for a particular patient. Typically, dosage levels range from about 10-1000 mg/dose for a 70 kg patient. Although one dose per day may be sufficient, up to 5 doses per day may be given. For oral doses, up to 5000 mg/day may be required. As the skilled artisan will appreciate, lower or higher doses may be required depending on particular factors. For instance, specific dosage and treatment regimens will depend on factors such as the patient""s general health profile, the severity and course of the patient""s disorder or disposition thereto and the judgment of the treating physician.